High-speed electrochemistry using ultramicroelectrodes

Miscellaneous · Sun Jan 01 00:00:00 EST 1989

OSTI ID:7109823

Walsh, M R

This research investigates the use of ultramicroelectrodes in performing electrochemistry on microsecond and nanosecond time scales. One purpose of this research was to look at new ways to apply ultramicroelectrodes to high speed experiments. Some of the aspects that are discussed in this thesis are: (a) A novel technique was developed for measuring currents on short time scales that involves conversion of the current to light using a light emitting diode and measuring the light intensity as a function of time using time correlated single photon counting (TCSPC). Computer processing of the light intensity data can convert this data back to current. The technique is capable of measurements on nanosecond time scales, but TCSPC requires tens or hundreds of millions of experiments to obtain a complete set of data and this frequently results in severe electrode fouling problems. (b) Potential step experiments were used instead of potential sweep experiments. Potential step experiments enable the separation in time of the faradaic and charging currents for chemical systems in which the faradaic impedance is greater than the uncompensated solution resistance. (c) For systems in which the faradaic impedance and uncompensated resistance are of the same order of magnitude, a computer simulation was developed which accounts for the interaction of the faradaic and double layer charging processes. (d) Application of short time scale experiments to the study of surface processes. Some processes studied in this work are the oxidation of clean platinum surfaces, electrode reactions of anthraquinone-2,6-disulfonic acid adsorbed on mercury, reductive hydrogen adsorption on platinum and double layer charging. (e) A study of the smallest available time constants was performed, taking into account non-idealities in the electrode such as stray capacitance and resistance of the electrode itself.

• Research Organization: Illinois Univ., Urbana, IL (United States)
• OSTI ID: 7109823
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ELECTROCHEMISTRY
ELECTRODES
TIME RESOLUTION
ADSORPTION
ANTHRAQUINONES
DIRECT CURRENT
HYDROGEN
MATHEMATICAL MODELS
MERCURY
MICROANALYSIS
OXIDATION
PLATINUM
PULSES
REDUCTION
AROMATICS
CHEMICAL REACTIONS
CHEMISTRY
CURRENTS
ELECTRIC CURRENTS
ELEMENTS
METALS
NONMETALS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PLATINUM METALS
QUINONES
RESOLUTION
SORPTION
TIMING PROPERTIES
TRANSITION ELEMENTS
400400* - Electrochemistry